For a long time, beeswax was has been in common usage as a natural wax for candles. Some time ago, paraffin came into existence, in parallel with the development of the petroleum refining industry. Paraffin is produced from the residue leftover from refining gasoline and motor oils. Paraffin was introduced as a bountiful and low cost alternative to beeswax, which had become more and more costly and in more and more scarce supply.
Today, mineral wax-based paraffin is the primary industrial wax used to produce candles and other wax-based products. Conventional candles produced from this wax material typically emit a, smoke and can produce a bad smell when burning. In addition, a small amount of particles (“particulates”) can be produced when the candle burns. These particles may affect the health of a human when breathed in. A candle that has a reduced amount of mineral wax-based paraffin would be preferable.
Accordingly, it would be advantageous to have other materials which can be used to form clean burning base wax for forming candles. If possible, such materials would preferably be biodegradable and be derived from renewable raw materials. The candle base waxes should preferably have physical characteristics, e.g., in terms of melting point, hardness and/or malleability, that permit the material to be readily formed into candles having a pleasing appearance and/or feel to the touch, as well as having desirable olfactory properties.
Additionally, there are several types of candles, including taper, votive, pillar, container candles and the like, each of which places its own unique requirements on the wax used in the candle. For example, container candles, where the wax and wick are held in a container, typically glass, metal or the like, require lower melting points, specific burning characteristics such as wider melt pools, and should desirably adhere to the container walls. The melted wax should preferably retain a consistent appearance upon resolidification.
In the past, attempts to formulate candle waxes from vegetable oil-based materials have often suffered from a variety of problems. For example, relative to paraffin-based candles, vegetable oil-based candles have been reported to exhibit one or more disadvantages such as cracking, air pocket formation, and a natural product odor associated with soybean materials. Various soybean-based waxes have also been reported to suffer performance problems relating to optimum flame size, effective wax and wick performance matching for an even burn, maximum burning time, product color integration and/or product shelf life. In order to achieve the aesthetic and functional product surface and quality sought by consumers of candles, it would be advantageous to develop new vegetable oil-based waxes that overcome as many of these deficiencies as possible.
Candles are often prepared by means of melt-processing. For purposes of commercial-scale manufacture, there can be economic advantage in the prospective utilization of wax powder compression technology. However, the production of a superior candle product by wax powder compression is not readily achieved. The compression-molding of a wax powder is affected by formulation variables, such as wax melting point, particle size distribution, cohesive nature of the wax, the number and quantity of additives such as air fresheners and colorants, and the like, and process variables, such as compression time and the degree of compression.
Today, candles are sold in the United States predominately for a decorating role and for adding ambiance to the home. An increasingly important aspect in marketing candles is the ability to deliver a fragrance. Here, candle manufacturers face constraints with the current wax systems due to chemical incompatibility of the fragrance and the petroleum-based waxes. In the preferred production methods (e.g., extrusion and compression molding), conventional materials have limited ability to hold fragrance. Overloading an extruded candle or compressed pillar candle with fragrance can lead to undesirable features, for example, fragrance weeping from the candle causing an oily surface and poor appearance.
There is continuing interest in the development of additional wax materials and candle products based on polyol ester materials, such as oilseed oils. In particular, there is a continuing interest in new wax materials which can be manufactured into candles by extrusion and compression technology.